This invention relates to a gauge for measuring the variation in the distance between the axle bore and the tread of a railroad car wheel at different angular positions on the wheel.
The Association of American Railroads has set a limit or tolerance on the variation in the distance measured along radial lines between the axle bore and the tread of a railroad car wheel. For some car wheels this tolerance is 0.0625 inches.
FIG. 1 shows a device presently used by railroad car wheel manufacturers to measure the variation in distance between the axle bore and tread of a car wheel. The presently used measuring device includes a U-shaped member having one short leg and one relatively long leg and an adjustable slide mounted on the long leg. A J-shaped member is rigidly attached to the adjustable slide and projects laterally therefrom. To position the measuring device on a railroad car wheel, the short leg of the U-shaped member is brought into engagement with the wheel tread and the adjustable slide is moved along the long leg of the U-shaped member until the tip of the J-shaped member just touches the axle bore. When the measuring device is so-positioned a thumbscrew is turned to lock the slide into position on the U-shaped member. In order to determine if the distance between the axle bore and the tread is within specification, the measuring device is rotated around the wheel. If an inspector cannot move the device around the wheel because the distance between the tread and the axle bore is too great, the thumbscrew is loosened and the slide is moved until the short end of the U-shaped member engages the tread and the tip of the J-shaped member just touches the axle bore at the greatest distance between the tread and the axle bore. As the measuring device is rotated, the inspector looks at the space between the short leg of the U-shaped member and the wheel tread to determine if this distance exceeds the tolerance set forth by the A.A.R. In other words, the inspector has to judge whether or not the space he sees is within or outside of the tolerance set by the A.A.R.
A problem with the present method of inspecting the tolerance between the tread and the axle bore is that the inspector has to decide whether the space between the short end of the U-shaped member and the tread is within the set tolerance. This becomes difficult in a close case.
An additional problem with the prior art measuring device is that it gives no indication of how far out of tolerance the wheel is.
It is desirable to provide a device for measuring the variation in distance between the axle bore and tread of a railroad car wheel which gives an inspector a direct read out of the variation in this dimension to thereby eliminate the need for an inspector to make a decision based on his judgement of what he sees.
It is further desirable to provide a device for measuring the variation in the distance between the axle bore and tread of a railroad car wheel which can be utilized on different sizes of railroad car wheels.